Binder resin composition and separator for electrochemical device comprising the same

Abstract

A binder resin composition comprising polyvinyl pyrrolidone-polyvinyl acetate block copolymer (PVP-co-PVAc). When introducing the binder resin composition to the porous coating layer of a separator for an electrochemical device, there an effect of significantly improving binding characteristics and heat resistance/safety.

What is claimed is: 
     
       1. A separator for an electrochemical device, comprising:
 a porous polymer substrate; and 
 a porous coating layer formed on at least one surface of the porous polymer substrate, 
 wherein the porous coating layer comprises inorganic particles and a binder resin composition consisting of a PVDF-based polymer, PVP and PVP-co-PVAc, 
 wherein based on 100 wt % of the combined weight of the binder resin composition with the inorganic particles in the porous coating layer, the binder resin composition is present in an amount of 10-30 wt %, the PVDF-based polymer is 5-20 wt %, the PVP is 1-3 wt % and the PVP-co-PVAc is 5-10 wt %, 
 wherein the PVP-co-PVAc has a molecular weight (Mw) of from 800,000 g/mol to 1,000,000 g/mol and, the content of the PVAc polymerization units in PVP-co-PVAc is 50-80 wt % based on the PVP-co-PVAc. 
 
     
     
       2. The separator for the electrochemical device according to  claim 1 , wherein the PVDF-based polymer comprises vinylidene fluoride homopolymer, PVDF-HFP, PVDF-CTFE, or two or more of them. 
     
     
       3. The separator for the electrochemical device according to  claim 1 , wherein the inorganic particles comprise at least one of BaTiO 3 , Pb(Zr,Ti)O 3  (PZT), b 1−x La x Zr 1−y Ti y O 3  (PLZT, 0<x<1, 0<y<1), Pb(Mg 1/3 Nb 2/3 )O 3 —PbTiO 3  (PMN-PT), hafnia (HfO 2 ), SrTiO 3 , SnO 2 , CeO 2 , MgO, NiO, CaO, ZnO, ZrO 2 , SiO 2 , Y 2 O 3 , Al 2 O 3 , SiC, or TiO 2 . 
     
     
       4. An electrochemical device comprising:
 a positive electrode; 
 a negative electrode; and 
 a separator interposed between the positive electrode and the negative electrode, 
 wherein the separator is the separator for the electrochemical device as defined in  claim 1 .